x86 64 - How to write a X86_64 _assembler_? - Stack Overflow
2010年6月19日 · Goal: I want to write an X86_64 assembler. Note: marked as community wiki. Background: I'm familiar with C. I've written MIPS assembly before. I've written some x86 assembly. However, I want to write an x86_64 assembler -- it should output machine code that I can jump to and start executing (like in a JIT).
assembly - x86 AND instruction - Stack Overflow
2014年1月9日 · In x86 64-bit, I have the following instruction: and $0xf, %eax The contents of %eax before and after remains 4. How is that possible? ANDing 100 & 1111 should result in 1100 which is 12, and...
x86 64 - Understanding %rip register in intel assembly - Stack …
2017年2月14日 · It's common to compile code for x86_64 target in PIC-compatible way (in some OS like OS X for Mac it is mandatory), while 32b x86 targets were usually using absolute code expecting particular position in memory.
Where can I find a list of x86_64 assembly instructions?
2017年4月26日 · As x86(_64) is a CISC processor, it has a big instruction set, but the compilers, unless you are optimizing, only use a "small" subset of it. You can check that disassembling binaries with objdump or your preferred disassembler.
Read and print user input with x86 assembly (GNU/Linux)
2014年5月5日 · I'm learning x86 assembly on GNU/Linux, and I'm trying to write a program that reads user input from stdin and prints it on stdout. The following code does work, but it prints extra characters if the size of the user-entered string is less than 100 bytes.
x86 64 - Assembly registers in 64-bit architecture - Stack Overflow
For more information should read x86-64 and x86-64 calling conventions. There's also a convention used in Plan 9 where. All registers are caller-saved; All parameters are passed on the stack; Return values are also returned on the stack, in space reserved below (stack-wise; higher addresses on amd64) the arguments.
assembly - Intel 64, rsi and rdi registers - Stack Overflow
But note that some instructions do still only work with some registers, for example rep movsb only works as a memcpy(rdi, rsi, rcx), and is in fact why RDI and RSI were chosen as the first 2 arg-passing registers in the x86-64 System V ABI: Some functions call memset or memcpy with their first 1 or 2 args, so inlining rep movsb/d is cheaper in ...
x86_64 - Assembly - loop conditions and out of order
2015年8月2日 · When optimizing for Intel CPUs, always put the flag-setting instruction right before the conditional jump instruction (if it's one of the simple ones listed in the table below), so they can macro-fuse into one uop in the decoders.
assembly - x86_64 registers rax/eax/ax/al overwriting full register ...
As it is widely advertised, modern x86_64 processors have 64-bit registers that can be used in backward-compatible fashion as 32-bit registers, 16-bit registers and even 8-bit registers, for exampl...
What does the instruction sete do in assembly? - Stack Overflow
2018年10月26日 · Assembly: CMOVB instruction in Intel x86-64 assembly. Related. 2. explanation of assembly code. 0.